Braking system



H. BAADE Sept. 24, 1940.

BRAKING SYSTEM v 2 Sheets-Sheet 1 Filed Jan. 3l, 1938 INVENTOR.

Bynmv Bnnoe W22,

Sept. 24, 1940. H. BAADE 2,215,602

BRAKING SYSTEM l Filed Jan. 31, 1938 2 sheets-she z 56.4 l '56.3 ae

a v 94 I 92 24a l III .360 A 356572 Y "H .nlll y 74a lill/gw i 56a 4m 374 380: :n Jaaa k l 3801,

368 376 35a f INVENTOR.

580 BY HENRY Bemba.`

f ATTORNEY,

Patented Sept. 24, 1940 UNITED STATES- PA'IENT OFFICE BRAKING SYSTEM Henry made, Detroit,- Mich., assigner to Bendix Products Corporation; South Bend, Ind., a corporation of Indiana Application January 31, 1938, Serial No. 187,905

13 Claims. (Cl. 18S-3) trolling a vacuum brake cylinder in accordance with the pressure in a hydraulic brake system.

Yet another object is toprovide means for controlling a differential air pressure cylinder by means of the hydraulic pressure in a hydraulic bra-ke system.

I prefer to accomplish these objects by providing, generally on the touring or tractor vehicle, a control valve adapted to control the differential air pressures applied to a power cylin- 0 der for operating the trailer brakes positioned on the trailer vehicle, which valve is operated by means of a hydraulic motor cylinder operatively connected with the pressure lines of the hydraulic brake system of the tractor vehicle.

I prefer to provide a valve having pressure responsive means responsive to the controlled pressure in the power brake cylinder, which pressure responsive means reacts against the force of the hydraulic actuating cylinder so that the hydraulic pressure and the controlled pressure are substantially proportionate.

The above and other objects and desirable particular constructions and arrangements of parts will be apparent upon reference to the following detailed description of several embodiments of 4my invention shown in the accompanying drawings in which:

Figure 1 is a diagrammatic plan view of tractor and trailer vehicles equipped according to my invention, and' in which the brakes of the trailer atmospheric-suspended cylinwhich the brakes of the trailer vehicle are ac- Figure 1 shows a touring vehicle, here illustratarc mounted wheels I4 and brakes i6. The automobile is provided with a hydraulic master cylinder I8 operated by a foot pedal 20 or corresponding device. Fluid from the master cylinder I8 is delivered by copper tubing 22 or the like and flexible hose 24 to the brakes I6 to operate them. Another tube 24a delivers iiuid from the master cylinder to my novel control valve 26. The automobile |0 has the usual internal combustion engine 28 with an induction pipe or intake manied as an automobile I0, having axles l2 on which fold 38 which provides a source of vacuum. A y

conduit 32 connects this source of vacuum to my novel valve 26 and the controlled pressure from my novel va-lve is conductedhto the rear of the vehicle by a conduit 34 terminating at a cut-olf valve 36.

Attached to therear of the automobile l0 is a towed vehicle or trailer 38 having an axle d0 on which are mounted wheels 42 and brakes 44. The brakes may be operated Aily-'Bowden cables 46, or the like, connectedfto atmospheric-suspended vacuum cylinders 48 secured to the structure of the trailer. The cylinders 4B have vacuum hoses 58 connected thereto leading to a common hose 52 extending forwardly of the vehicle and connected by a flexible hose 54 to the tractor vehicle controlled pressure conduit 34 through the cut-oil valve 36, which, of course, is opened when the trailer is attached. Mynovel valve 26 is shown indetail in Figure 3.( It comprises a pair of casing shells 56 and 58 having clamped between them a diaphragm 60, having an annular ring of perforations 62. The lower shell 56 and diaphragm .60 form an air chamber 64 communicating with an air cleaner 66 by means of a port 68. The diaphragm' 60 and upper casing shell 58 form two chambers separated at times by an annular wall 10. The outer chamber 12 is a .vacuum chamber communicating with the conduit 32 .by a'port 14 and the inner chamber 16 is a controlled pressure chamber communicating with the conduit 34 by a port 18.

A plunger 80 is secured to the center of the diaphragm and extends through suitable packings out of the casingshell, Secured to the plunger on opposite sides of the diaphragm are a pair of valve discs 82 and 84. The disc 82 is on the air chamber'side, has perforations corresponding to the perforations 62 of the diaphragm 68, and is of such diameter that, when the plunger is moved upwardly this disc presses the diaphragm against `the edge of the annular wall 10 separating the two chambers l2 and 16. The other disc 84 is on the opposite side of the diaphragm., is not perforated, is provided with an annular edge ada-pted to engage and seal against the diaphragm radially outwardly of the perforations 62, and is of slightly less diameter fill than the annular wall 10. When the plunger is raised to its extreme position, the annular diaphragm engaging edge of the disc 84 ls lifted free of the diaphragm.

VA pair of brackets 96 secured to the casing members carry a hydraulic cylinder 88 having a piston 90 engaging the plunger 00.` The cylinder is provided with an inlet port 92,receiving the conduit 24a, and the usual bleed screw 94. Compressed between a washer 96 abutting against adjusting nuts 98 threaded on the plunger 80, and the outer surface of the casing shell 58 is a coil spring |00 which normally urges the plunger upwardly.

In operation it will be noted that with the plunger 80 in its normal position as determined by the spring |00, air at atmospheric pressure enters the air chamber 64 from the air cleaner 66 through the port 68, and passes from the air chamber 64 into the controlled pressure chamber 84 through the perforations 62 in the diaphragm 60 and under the edge of the valve disc 84. Consequently the pressure in the controlled pressure conduit 34, the exble hose 64, the conduits 50 and 52 and the cylinders 48 is atmospheric and the trailer brakes 44 are released.

Now when the driver of the automobile I0 applies the brakes I4 of the automobile by pressing on the foot pedal 20, hydraulic pressure is created in the line 24a which acts on the piston 90 to force the plunger downwardly when the force on the piston exceeds the force of the spring |00. When this occurs the valve disc 84 seats on the diaphragm |50, closing communication between the air chamber 64 and the controlled pressure chamber 16 through the ports 62, then the diaphragm 60 is lifted from the edge of the annular wall 10 permitting communication between the vacuum chamber 12. This communication with the vacuum chamber withdraws air from the controlled pressure chamber 16, the conduit 34, hose 54, conduits 50 and 52, and the cylinders 48, thereby applying the trailer brakes 44.

The vacuum in chamber 16 reacts on the diaphragm 60 in opposition to the hydraulic pressure on the piston ,90 and, if this pressure is not too great (i. e., if-the brakes are applied lightly) the valve will move back to a lapped position wherein the diaphragm is in contact with both the annular wall 10 and the valve disc 84. Then, if the brakes are applied more strongly or are slightly released, communication is reestablished in one direction or the other to increase or decrease the amount of vacuum in the controlled pressure chamber 16.

It will be observed that by using my novel device; the trailer brakes are applied in conformity with the application of the tractor brakes and without the use of a very large volume of hydraulic uid. This system is particularly suitable ior house trailers in view o! the fact that the majority of modern passenger automobiles are equipped with hydraulic brakes, but I do not desire to limit myself to this application solely.

In the arrangement of Figures 2 and 4 corresponding parts are designated by the same reference numerals plus |90. Referring to the valve |26 of Figure 4, the casing shells |66 and |68 are arranged in inverse positions to those of the valve 26 of Figure 1. With this valve the vacuum chamber |12 and the controlled pressure chamber |16 are normally in communication so that vacuum is transmitted through the conduit |84, the Ilexible hose |64 and the conduits |68 and |62. The conduits |60 are connected to the rear ends of the cylinders |48, and an extensionof the vacuum line |32 comprising a conduit |32a, a flexible hose |32b, and conduits |32c and |32d are connected to the front ends of the cylinders |48. When the valve |26 is operated air is admitted to the controlled pressure chamber and transmitted through the lines to the rear of the cylinders |48 thereby applying the brakes. This system is called a vacuum-suspended system while that of Figure 1 .is called an atmospheric-suspended system.

In Figure 5 I have shown a modied valve for the atmospheric-suspended system of Figure 1. In this figure parts corresponding to parts of Figure 1 are designated by the same reference numeral plus 200. In this valve the plunger 280 is provided with a reduced portion 280e, a cut-away portion 280b and a longitudinal groove 280e.A With the plunger in its normal position air is transmitted through the air port 268 past the reduced and cut-away portions 280a and 280i) of the plunger 280 to the controlled pressure port 218. When hydraulic pressure acts on the piston 290 the plunger 280 is moved downwardly so that the airport 268 is rst cut oif and then the vacuum port 214 is opened and put into communication with the controlled pressure port 218. The pressure in the controlled pressure port 218 is at all times transmitted through the slot 280c to the controlled pressure chamber 216 where it reacts upon the upper face of the diaphragm 260 to balance the force of the piston 290 in the same manner as described with relation to the valve 26. The valve of Figure 6 is a modication suitable for use in a vacuum-suspended system such as Figure 2. In this modiiication parts corresponding to parts of Figure 1 are designated by the same reference numerals plus 300.

In this modification the valve elements comprise a plunger 380 secured to the diaphragm 960, a floating lever 380a engaged by the plunger and engaging a pair of poppet valves 380b and 880e respectively adapted to close the air ports 388 and the vacuum port 314. A biasing spring 980d on the stem of the valve 380b insures that one valve closes before the other opens and vice versa. The plunger 380 is normally urged upwardly by the spring 400 in which position the valve 380e is lifted admitting vacuum from the port 314 to the controlled pressure chamber 816. When the valve is operated by forcing the plunger downwardly, valve 380e iirst closes, cutting off the vacuum, and then valve880b opens, admitting air to the controlled pressure chamber. Vacuum is normally present in the chamber 312 on the upper side of the diaphragm, a port 31411'. being provided for this purpose. When air is admitted to the controlled pressure chamber 816 it reacts against the diaphragmv 860 in opposition to the force ot the piston 390 thereby providing proportionate braking on the trailer as previously described.

While I have described several embodiments of my invention, it is not my'intention to be limited to those embodiments or otherwise than by the terms of the appended claims.

I claim: f'

1. In combination, a tractor, a trailer, brakes on each, hydraulic pressure creating means ior actuating the tractor brakes. diiierential air pressure operating means for the trailer brakes, a source oi' dlierential air pressure, a. valve for controlling said diierential air pressure, hydraulic pressure actuating means on said valve, connections between the ,hydraulic pressure `creating means and the hydraulic pressure actuating means, and connections between said valve and said source of differential air pressure and between said valve and said diierential air pressure operating means.

2. In combination, a tractor, a trailer, brakes on each, hydraulic pressure creating means for actuating the tractor brakes, 'diierential air pressure operating means for the trailer brakes, a source of diierential air pressure, a valve for controlling said diii'erential air pressure, hydraulic pressure actuating means on said valve, connectionsbetween the hydraulic pressure creating means and the hydraulic pressure actuating means, and connections between said valve and said source of diierential air pressure and between said valve and said differential air pressure operating means, said valve having a pressure responsive element reacting against said hydraulic pressure actuating means.

3. In combination, a tractor, a trailer, brakes on each, hydraulic pressure creating means for actuating the tractor brakes, diierential air pressure operating means for the trailer brakes, a source of diierential air pressure, a valve for controlling said differential air pressure, hydraulic pressure actuating means on said valve, connections between the hydraulic pressure creating means and the hydraulic pressure actuating means, and connections between said valve and said source of differential air pressure and between said valve and said diierential air pressure operating means, said valve having a spring and a pressure responsive element reacting against said hydraulic pressure actuating means.

4. A combination braking system for vehicles comprising hydraulic brakes and differential air pressure operated brakes, a source of differential air pressure, connections between said source and said differential air pressure operated brakes, a control valve in said connections, and means in said valve responsive to the pressure in the hydraulic brakes for actuating said valve.

5. A combination braking system for vehicles comprising hydraulic brakes and differential air pressure operated brakes, a source of differential air pressure, connections between said source and said differential air pressure operated brakes, a control valve in said connections, means in said valve responsive to the pressure in the hydraulic brakes for actuating said valve, and means in said valve responsive to the diirerential air pressure opposed to said rst named means.

6. A combination braking system for vehicles comprising hydraulic brakes and differential air pressure operated brakes, a source of diierential air pressure, connections between said source and said diilerential air pressure operated brakes, a control valve in said connections, means in said valve responsive-to the pressure in the hydraulic brakes for actuating said valve, and a spring opposed to said rst named means.

7. A combination braking system for vehicles comprising hydraulic brakes and dierential air pressure operated brakes, a source of diilerential air pressure, connections between said source and said diierential air pressure operated brakes, a control valve in said connections, means in said valve responsive to the pressure in the hydraulic brakes for actuating said valve, a spring opposed to said rst named means, and means for adjusting the force exerted by said spring.

8. In combination, a tractor, a trailer, brakes on each, hydraulic pressure creating means for actuatingthe tractor brakes, vacuum cylinders for operating the trailer brakes, a source of vacuum, a valve for controlling the vacuum, hydraulic pressure actuating means on said valve, connections between the hydraulic pressure creating means and the hydraulic pressure actuating means, and connections between said valve and said source of vacuum and between said valve and said vacuum cylinders.

9. In combination, a tractor, a trailer, brakes on each, hydraulic pressure creating means for actuating the tractor brakes, vacuum cylinders for operating the trailer brakes, a source of vacuum, a valve for controlling the vacuum, hydraulic pressure actuating means on said valve, connections between the hydraulic pressure creating means and the hydraulic pressure actuating means, and connections between saidvalve and said source of vacuum and between said valve and said vacuum cylinders, said vacuum cylinders being of the atmospheric-suspended type.

10. In combination, a tractor, a trailer, brakes on each, hydraulic. pressure creating means for actuating the tractor brakes, vacuum cylinders for operating the trailer brakesa source of vacuum, a valve for controlling the vacuum, hydraulic pressure actuating means on said valve, connections between the hydraulic pressure creating means and the hydraulic pressure actuating means, and connections between said valve and said source of vacuum and between'said valve and said vacuum cylinders, said vacuum cylinder being of the Vacuum-suspended type.

11. In combination, a tractor, a trailer, brakes on each, hydraulic pressure 'creating means for actuating the tractor brakes, vacuum cylinders for operating thetrailer brakes, a source of vacuum, a valve for controlling the vacuum, hydraulic pressure actuating means on said valve, connec tions between the hydraulic pressure creating means and the hydraulic pressure actuating means, and connections between said valve and said sourceof vacuum and between said valve and said vacuum cylinders, said vacuum cylinders being of the atmospheric-suspended type, and said valve having a vacuum responsive element opposed to said hydraulic pressure actuating means.

12. In combination, a tractor, a trailer, brakes on each, hydraulic pressure creating means for actuating the tractor brakes, vacuum cylinders for operating the trailer brakes, a source of vacuum, a valve for controlling the vacuum, hydraulic pressure actuatingmeans on said valve, connections between the hydraulic pressure creating means and the hydraulic pressure actuating means, and connections between said valve and said source of vacuum and between said valve and said vacuum cylinders, said vacuum cylinders being of the vacuum-suspended type, and said valve having an air pressure responsive element opposed t0 said hydraulic pressure actuating means.

13. A combination braking system comprising hydraulically operated brakes and pneumatically operated brakes. a hydraulically operated element 4operated by pressure on the hydraulically operated brakes, valve elements moved by said hydraulically actuated element for controlling the l 

